The present invention relates to a bar code reader, and more particularly, to a bar code discriminating apparatus for reading bar codes.
In a conventional bar code reader, it is difficult to extract only a signal corresponding to the bar code (a bar code signal) from a scanned signal which a scanner delivers responsive to scanning a surface containing a bar code label and the area surrounding the bar code label. For code extraction, it is necessary to read only the bar code signal, if the reading time is to be decreased. It is desirable to reduce reading errors and to simplify a reading circuit configuration. It is also desirable to discriminate between the bar code signal and a noise signal corresponding to the surrounding area. In order to discriminate the bar code signal, the invention counts the number of black bars and white bars, which build up the bar code. When the number of the black bars and white bars reaches a predetermined value, the series of the black bars and white bars is regarded as being a complete bar code to be read.
However, in practice, the prior art bar code discriminating technique frequently detects a bar code erroneously because the noise signal delivered from the area surrounding the bar code frequently contains random pulses which satisfy the discriminating condition. In this case, a bar code reader wastefully performs a reading operation and gives an incorrect output, which causes an increase in an error reading rate.